The International Space Station suffered a problem with half of its vital cooling system Wednesday (Dec. 11), resulting in a partial power down of some non-critical systems, NASA officials say.

According to a NASA statement, "at no time was the crew or the station itself in any danger." The six astronauts and cosmonauts aboard the orbiting laboratory went to sleep as regularly scheduled with no concern for their safety, the statement said.

On Wednesday, one of the two pumps used to circulate ammonia coolant on the outside of the space station shut down after lower than normal temperatures were detected. The shutdown cut off half of the space complex's ability to regulate the temperatures for both its internal and external systems.

328KF

Just trying to figure what might happen going forward here. It seems more than coincidence that two pump modules (PM) have failed on the same loop. The best I have been able to find is that there are three PM spare ORUs left aboard. I wonder how wise it would be to keep plugging new PM's in if there might be something else in the system causing them to fail.

With limited spares and a long life ahead for ISS, is there any way of getting new spares up there, assuming they could be built now? It looks like the SpaceX Dragon can handle the weight (780lbs) but not the volume in the trunk. I suppose if things got desperate, some modification could be made to Dragon to accommodate it.

How about Orbital Sciences' Cygnus? Could they transport ORUs uphill in that module with the hatch size?

328KF

NASA Spaceflight has a very thorough article on the issue. They report:

The ETCS is not to be confused with the Photovoltaic Thermal Control System (PVTCS), which is completely separate from the ETCS and is used only to cool the solar arrays and associated power generation equipment, and not the main ISS structure, cooling for which is provided by the ETCS.

The current FCV issue is located within ETCS loop A, and thus has no relation whatsoever to the Pump Flow Control Subassembly (PFCS) leak and associated replacement earlier this year, as that issue related to the PVTCS only.

But the entire PM still needs to be replaced, and that presents another problem:

However, complicating matters is that EVAs are currently suspended following a water leak inside Italian astronaut Luca Parmitano’s spacesuit helmet during an EVA in July, an event which could easily have led to him drowning.

The leak occurred inside Extravehicular Mobility Unit (EMU) number 3011... NASA had been planning to wait to return EMU 3011 to Earth aboard a SpaceX Dragon vehicle and deliver a new EMU in its place before clearing EVAs to resume, however the next Dragon vehicle is not scheduled to arrive at the ISS until at least late February next year.

Robert Pearlman

quote:Originally posted by 328KF:It seems more than coincidence that two pump modules (PM) have failed on the same loop.

According to NASA, the pump module itself did not fail. Rather, a flow control valve inside the pump module is not "positioning properly," and whether that is a hardware problem or something that can be addressed through another solution is still to be seen.

As Doug Wheelock (who led the spacewalks that installed this pump module) wrote on Twitter tonight:

Working with our teams in Mission Control to develop a recovery plan. Too early to say if we'll need EVA(s).

NASA had no pressing need to schedule a spacewalk before today, hence the stand down since the problem with Luca Parmitano's suit. But, the agency has said that if an emergency warranted it, they would weigh the risks of another suit failure versus the need to repair the station before deciding whether to press forward with a spacewalk.

At the moment, Loop A is hovering around -35 degrees Celsius, where as Loop B is +4 degrees.

Robert Pearlman

Space station capcom Josh Matthew told the crew this morning (Dec. 12) that the ground today will be manually cycling the position of the flow control valve as a first attempt at troubleshooting the low temperatures on Loop A.

Matthew said Mission Control was still in "data gathering mode" and didn't have any further guidance for the coming days as of yet.

The planned launch of a private cargo spacecraft to the International Space Station may need to be delayed if a problem with the orbiting outpost's cooling system is not first resolved, NASA officials said Thursday (Dec. 12).

...with some redundant systems offline however, the space station is not currently in a good configuration to receive a visiting vehicle.

Orbital Sciences Corporation of Virginia had been readying its Cygnus unmanned spacecraft for a launch to the space station as early as Wednesday (Dec. 18) on the first of the company's eight contracted missions to deliver equipment and supplies for the station's crew. That flight may still go forward as scheduled but NASA's managers delayed their "go/no go" decision until Monday.

Headshot

On a somewhat related topic, has the faulty U.S. EVA suit been returned to Earth yet? If so, has NASA discovered the cause of the suit's "water" leak?

328KF

Headshot, see the end of my last post above.

Robert Pearlman

Although the formal mishap investigation has not concluded, NASA has become comfortable enough with their understanding of the issue to approve contingency spacewalks, as needed. The suspect component from Luca Parmitano's suit was returned to Earth on the last Soyuz, and tests of suits still on the space station have not shown additional leaking.

With regards to launching more pump modules, I am awaiting further details, but per NASA, replacements could be launched on either HTV or Dragon, and possibly ATV.

Headshot

quote:Originally posted by 328KF:Headshot, see the end of my last post above.

328KF, thanks. For some reason I was under the impression that the suit had been returned. I idiotically glided over the last part of your post. My laziness.

JBoe

Has the coolant loop problem been fixed? If not, is there any updates to the Orbital launch next week?

Robert Pearlman

It has not been fixed, though troubleshooting was on hold today as ground teams reviewed their options, including removing and replacing the pump module during one or more spacewalks to possibly begin as early as Thursday (Dec. 19).

If they decide to go forward with the spacewalk(s), then almost certainly Orbital's launch will be delayed.

At this point however, Orbital is still preparing for a Wednesday (Dec. 18) launch. The decision whether to press forward will be made on Monday.

Robert Pearlman

NASA update (Dec. 14, 2013)

Overnight, engineers conducted testing with a component in the Pump Module called a Radiator Return Valve, which is a ball valve that operates in concert with the suspect Flow Control Valve in the pump to control heating in the cooling lines to the Interface Heat Exchangers.

The Radiator Return Valve was commanded to various positions to see how the Flow Control Valve might be placed in a fixed position to help actively control cooling loop A, and in turn, allow the system to warm up sufficiently so that the heat exchangers in the loop can operate at a proper temperature.

Engineers continue to pore over the data and other techniques to manage the flow control valve. The cooling of station systems is currently being managed through cooling loop B that employs a pump module on the port truss.

In the meantime, Expedition 38 crewmembers Rick Mastracchio and Michael Hopkins worked Saturday in the Quest airlock to begin preparing their spacesuits in the event they are called upon to conduct spacewalks to change out the faulty pump module.

If managers direct the crewmembers to perform those spacewalks beginning late next week, the launch of the Orbital-1 mission would be delayed until January.

Robert Pearlman

NASA update (Dec. 15, 2013)

NASA engineers continued efforts Sunday to regulate temperatures in one of two cooling loops on the International Space Station affected by the malfunction last week of a flow control valve in a cooling pump on the station’s starboard truss.

Efforts overnight to fine-tune the position of an isolation valve associated with the flow control system in the Pump Module into a "sweet spot" to assist the faulty Flow Control Valve in regulating the affected cooling loop's temperatures were still being evaluated as engineers continue to review the data, valve positioning techniques and additional methods of temperature management in the loop.

Meanwhile, parallel work is ongoing to either enable Orbital Sciences Corp. to launch its Antares rocket and the Cygnus cargo craft from the Wallops Flight Facility, Va. on Thursday night (Dec. 19) at 9:19 p.m. EST on its first resupply mission to the space station, or for Expedition 38 astronauts Rick Mastracchio and Michael Hopkins to mount a suite of spacewalks beginning Thursday to replace the faulty pump.

The space station program continues to keep both options on the table pending further engineering analysis and troubleshooting efforts on the station's cooling system.

Aboard the space station, Mastracchio and Hopkins continued to prepare their spacesuits and other equipment in the Quest airlock Sunday should they be called upon to conduct spacewalks to replace the pump module.

Robert Pearlman

NASA's space station flight controllers are making headway towards restoring the outpost's coolant system by sending commands to the Loop A radiator return isolation valve.

The hope is that this valve can be positioned in such a way to help maintain the proper temperature in the loop.

"I am pleased to report that the ground teams are doing an awesome job getting smarter on managing the Loop A temperatures," Ringo said. "They have been doing this through commanding the radiator return isolation valve."

"We're continuing to work getting the loop in a good state that would allow reintegration of the heat exchangers. Folks are currently looking at that data," she added.

"Big picture wise, we may or may not attempt to reintegrate the lab's heat exchanger this evening," Ringo advised the crew.

If the heat exchanger can be reintegrated, it is expected that NASA will give the go for Orbital Sciences to proceed with its first contracted Cygnus resupply flight to the space station, currently targeted to lift off on Thursday (Dec. 19).

A commercial cargo flight to the International Space Station (ISS) has been postponed so astronauts on board the orbiting outpost can proceed with a series of spacewalks to repair a critical cooling system.

NASA on Tuesday (Dec. 17) announced that the launch of Orbital Sciences' Cygnus spacecraft would be delayed to January to give station crew members the time to replace a pump module that stopped working properly on Dec. 11.

NASA is now planning for two Expedition 38 astronauts to venture outside the station on Dec. 21, 23 and, if needed, Christmas day, Dec 25. Flight engineers Rick Mastracchio and Mike Hopkins will remove the pump module that has a failed valve and replace it with one of three spares stored on the exterior of the station.

Robert Pearlman

quote:Originally posted by 328KF:With limited spares and a long life ahead for ISS, is there any way of getting new spares up there, assuming they could be built now?

I asked NASA's ISS program manager Mike Suffredini about this at Wednesday's (Dec. 18) press conference:

The [pump module] that failed [and was returned to Earth by STS-135] we're repairing and we're going to have to do another build of pumps just for the life of ISS in general.

The cargo capabilities that we have today can carry every ORU we have in the fleet we can take to orbit.

There are a couple of spares we had not intended to build or didn't think we would need. One was the solar array, and the other was the big radiators. If we had to spare either of those two, we'd have to figure out another path then the existing systems we use today.

Other than that, all the ORUs we have and can expect to change out on orbit we can carry to orbit.

Suffredini also said that they believe they can repair the current pump module that will be replaced during the upcoming spacewalks by adding an exterior valve during a future EVA.

Astronauts preparing to spacewalk outside the International Space Station are outfitting their spacesuits with an unusual device: a makeshift snorkel.

The astronauts, whose task it is to repair a critical cooling system necessary for keeping the outpost fully powered, have an additional concern to the "normal" challenges of a quickly-planned extra-vehicular activity (EVA, spacewalk). There is also a slight possibility their helmets could flood with water.

Astronauts working speedily outside the International Space Station removed a malfunctioning pump module ahead of schedule, potentially ruling out the need for a Christmas Day spacewalk to continue repairs to the orbiting outpost's critical cooling system.

Expedition 38 flight engineers Rick Mastracchio and Mike Hopkins ventured outside of the station at 6:01 a.m. CST (1101 GMT) Saturday (Dec. 21), just ten days after a flow control valve ceased working properly inside the ammonia pump module they were set to remove and replace during another six-and-a-half-hour spacewalk on Monday.

Saturday's spacewalk came to its end at 11:29 a.m. CST (1729 GMT), five hours and 28 minutes after it began.

Robert Pearlman

Following the successful completion of Saturday's spacewalk, NASA delayed the next planned excursion from Monday to Tuesday (Dec. 24).

The extra day will allow time to resize a spare spacesuit for Rick Mastracchio. During repressurization of the station's airlock following Saturday's spacewalk, a spacesuit configuration issue put the suit Mastracchio was wearing in question for the next outing.

Astronaut Koichi Wakata reported the issue to the ground during the airlock's repressurization.

"EV1 [Mastracchio] inadvertently moved the water switch [on his suit] to on and it was quickly returned to off," Wakata told Mission Control.

During a later call up to the station's crew, flight controllers expressed concern about the "water in the sumblimator" in Mastracchio's suit, and sent up procedures to dry it out.

According to NASA, this issue is not related to the helmet water leak that cut short a spacewalk in July.

Due to the slip, if a third spacewalk is needed to complete the repair of the space station's cooling system, it will now take place no sooner than Dec. 26, rather than Christmas Day, as originally scheduled.

Astronauts aboard the International Space Station received a gift just in time for Christmas: a new pump module to repair their ailing cooling system and to restore the outpost to full power.

Expedition 38 flight engineers Rick Mastracchio and Mike Hopkins embarked on their second spacewalk together at 5:53 a.m. CST (1153 GMT) on Tuesday morning (Dec. 24) to complete the work they began on Saturday to replace a pump module with a faulty flow control valve.

"Houston from the airlock, we'd just like to say thanks to all the great folks doing all this hard work to get this space station back up and running," Mastracchio radioed at the end of the spacewalk, which concluded at 1:23 p.m. CST, seven hours and 30 minutes after it began.

"No, thank you guys," astronaut capcom Doug Wheelock replied from NASA's Mission Control in Houston. "It is the best Christmas ever. Thanks, guys."

"I'd just like to add to that," Hopkins said. "Fantastic work, merry Christmas to everybody. It took a couple of licks to get her done, but we got it."

Robert Pearlman

NASA release

Station's replacement pump successfully restarted

Following two spacewalks to replace a degraded pump module on the truss, or backbone, of the International Space Station, flight controllers in the Mission Control Center at NASA's Johnson Space Center in Houston successfully restarted the new pump Tuesday night (Dec. 24).

The pump module controls the flow of ammonia through cooling loops and radiators outside the space station, and, combined with water-based cooling loops inside the station, removes excess heat into the vacuum of space.

The new pump now is considered fully functional, but it will take some time to fully reintegrate the pump and Loop A of the two-loop external cooling system. Teams at mission control are following a schedule that should allow the restored cooling loop to be fully activated and integrated into the station's cooling system on Christmas Day, Dec. 25.

Electrical systems that depend on cooling from Loop A will be repowered or moved back from their temporary support on Loop B gradually on Thursday, Friday and throughout the weekend.